The 180º method:

Number 1 piston at Top Dead Center (TDC) on compression stroke.
Adjust intake valve on #2 and #7;exhaust valves #4 and #8.

Rotate crankshaft 180 degrees clockwise and adjust intake valve on #1 and #8;
exhaust valves #3 and #6.

Rotate crankshaft 180 degrees again (TDC) and adjust intake valves #3 and #4;
exhaust valves #5 and #7.

Rotate crankshaft again 180 degrees and adjust intake valves #5 and #6;
exhaust valves #1 and #2.